By the use of various culture techniques and serologic methods we propose to determine the frequency of latent chlamydial infections in commonly used laboratory and domestic animals. Suitable animal models will be developed to study the pathophysiology of chlamydial infections and to investigate potentially useful drugs for the treatment of chlamydial infections in man. Sporadic human endemics, thought to arise from man's contact with various mammalian or avian species, will be investigated for chlamydial etiology. Various culture techniques and serologic methods will be applied, and the epidemiology of the ocular disease will be studied in detail.